Free Online Diff Checker - Compare Text, Code & Files Instantly
The fastest online diff checker to compare two texts, find differences between files, and merge changes. Whether you need a text difference checker, code diff checker, or file diff checker — this free tool handles it all with instant results.
100% private and secure — all text comparison happens directly in your browser. No uploads, no servers, no tracking. Works offline, supports large files with 25,000+ lines, and is completely free for personal and commercial use.
Why Use This Online Diff Checker?
Unlike other difference checkers that require uploads or subscriptions, our diffchecker online tool is completely free, works instantly in your browser, and keeps your data private.
Instant Text Diff
Compare text online in real-time with our optimized diff algorithms. See differences as you type — no waiting, no processing delays.
100% Private & Secure
Your text never leaves your device. Unlike other online text diff checkers, we don't upload your data to any server.
Smart Merge Tool
Find differences between two texts and merge them intelligently. Accept or reject individual changes, then export the combined result.
Large File Support
Compare two text files with 25,000+ lines efficiently. Collapse unchanged sections to focus on what matters.
Secure URL Sharing
Share your diff online via a unique URL. All data is encoded directly in the link — nothing stored in databases.
Works Offline
This text comparator works without internet once loaded. No server dependency means you can compare text anytime, anywhere.
Split & Unified Views
Choose between side-by-side split view or unified diff view. Switch instantly based on your preference.
Mobile Friendly
Fully responsive design works on desktop, tablet, and mobile. Compare text on any device without installing apps.
No Sign-up Required
Start comparing immediately — no registration, no email, no accounts. This diffchecker free tool respects your time and privacy.
What Can You Compare?
Our versatile online diff checker handles any text-based content. From source code to configuration files, documents to data exports — if it's text, you can compare it.
Code Diff Checker
Compare code changes across any programming language. Our code diff checker shows character-level differences, making it perfect for code reviews and debugging.
- JavaScript, TypeScript, Python
- Java, C++, C#, Go, Rust
- HTML, CSS, SCSS, LESS
- SQL queries and procedures
- Shell scripts and configs
Text Compare Tool
Find differences between two texts instantly. Whether comparing documents, articles, or any written content, our text difference checker highlights every change.
- Document version comparison
- Article and blog revisions
- Email and message drafts
- Legal document changes
- String difference checker
File Diff Checker
Compare configuration files, data exports, and structured documents. Our file difference checker supports all text-based formats with syntax-aware highlighting.
- XML diff checker for configs
- JSON comparison and validation
- YAML and TOML files
- CSV and data exports
- Log file analysis
How to Compare Two Texts Online?
Using our online text compare tool is simple. Follow these four steps to check diff online and find all differences between your texts:
Paste Original Text
Enter or paste your original text, code, or file content in the left editor panel.
Paste Changed Text
Enter the modified or updated version in the right editor panel for comparison.
View Differences
Instantly see all differences highlighted — red for deletions, green for additions.
Merge & Export
Use the merge tool to combine changes, then copy or download your result.
Pro tip: Use the "Collapse" mode to hide unchanged lines and focus only on differences.
Switch between "Split" and "Unified" views based on your preference for side-by-side or inline comparison.
Frequently Asked Questions
What is a diff checker?
A diff checker (also called difference checker or text comparator) is a tool that compares two texts and highlights the differences between them. It shows additions, deletions, and modifications, making it easy to see exactly what changed.
How do I compare two texts online?
Simply paste your original text in the left panel and the changed text in the right panel. Our text difference checker instantly highlights all differences — red backgrounds show removed content, green shows additions.
Is this online diff checker free?
Yes, this diffchecker is 100% free for both personal and commercial use. No sign-ups, no usage limits, no hidden fees, and no premium tiers.
Is my data secure with this diff checker online tool?
Absolutely. All text comparison happens locally in your browser — your content is never uploaded to any server. Even the share feature encodes data directly in the URL without storing anything.
Can I use this as a code diff checker?
Yes! Our tool works excellently as a code diff checker for any programming language — JavaScript, Python, Java, C++, HTML, CSS, SQL, and more.
Does this file diff checker support large files?
Yes, our file difference checker efficiently handles files with 25,000+ lines. Use the 'Collapse' mode to hide unchanged sections and focus on differences.
How does the merge feature work?
Click 'Start Merge' after comparing texts. You'll see each difference with Accept/Reject buttons. Choose which changes to keep from either version, then copy or download the merged result.
Can I share my diff comparison with others?
Yes! Click the 'Share' button to generate a unique URL containing your comparison. The text is encoded directly in the URL — nothing is stored on servers.
Does this diff checker work offline?
Yes, once the page loads, you can use this text comparator without internet connection. All processing happens in your browser.
What's the difference between split and unified view?
Split view shows original and changed text side-by-side in two columns — great for comparing longer texts. Unified view shows everything in a single column with changes inline.